Berlin 2008 – wissenschaftliches Programm
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BP: Fachverband Biologische Physik
BP 28: Molecular Recognition
BP 28.5: Vortrag
Freitag, 29. Februar 2008, 11:45–12:00, PC 203
Switchable DNA layers - a versatile instrument for protein detection on a chip — •Wolfgang Kaiser1, Erika Pringsheim1, Jelena Knezevic1, Kenji Arinaga2, Shozo Fujita2, Naoki Yokoyama2, Ulrich Rant1, and Gerhard Abstreiter1 — 1Walter Schottky Institut, Technische Universität München, Deutschland — 2Fujitsu Laboratories Ltd., Atsugi, Japan
We present a new technique to detect label free protein targets by switchable DNA-layers. The concept is to "switch" surface bound DNA molecules by applying external AC fields. By varying the electrical field the DNA molecule changes its orientation from lying to upright and back, which is monitored in real-time by observing the fluorescence of a dye-label on the distal end of the DNA. Distance dependent energy transfer from the dye to the metal surface governs the fluorescence emission.
For the detection of proteins, the DNA is additionally functionalized with a chemical label which acts as a specific binding site for proteins. When proteins bind to this label, we observe a distinct shift in the switching behavior. At high switching frequencies DNA-protein-complexes can be discriminated from uncomplexed DNA due to their different hydrodynamic mobility. We present sensing experiments of streptavidin and antibiotin, and discuss the influence of the proteins' weight and hydrodynamic diameter (measured by dynamic light scattering) to the switching dynamics.
Switchable DNA layers make the determination of the hydrodynamic mobility / weight of proteins in a chip-compatible format possible.